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Powerful Tropical Cyclone Gita posed an increasing threat to Tonga on Sunday night. At 10:00 p.m. EST the center of Tropical Cyclone Gita was located at latitude 21.7°S and longitude 173.2°W which put it about 120 miles (195 km) east of Nuku’Alofa, Tonga. Gita was moving toward the west at 13 m.p.h. (21 km/h). The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 155 m.p.h. (205 km/h). The minimum surface pressure was 944 mb. Tropical Cyclone Gita was the equivalent of a major hurricane.

The circulation of Tropical Cyclone Gita is very well organized. There is a circular eye at the center of circulation. A ring of strong thunderstorms surrounds the eye and the strongest winds are occurring in that eye. Bands of showers and thunderstorms are revolving around the core of Tropical Cyclone Gita. Storms in the core are generating strong upper level divergence which is pumping mass away in all directions. Winds to hurricane/typhoon force extend out about 50 miles (80 km) from the center of circulation. Winds to tropical storm force extend out about 165 miles (270 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Gita is 23.6. The Hurricane Size Index (HSI) is 16.0 and the Hurricane Wind Intensity Size Index (HWISI) is 39.6. Those indices indicate that Gita will be capable of causing major damage when it moves over Tonga on Monday.

Tropical Cyclone Gita will be moving through an environment favorable for strong tropical cyclones during the next 24 to 48 hours. Gita will move over water where the Sea Surface Temperature is near 30°C. The upper level winds are weak and there is little vertical wind shear. The favorable environment could allow Tropical Cyclone Gita to intensify more before it reaches Tonga.

Tropical Cyclone Gita is moving north of a subtropical ridge which is steering the tropical cyclone toward the west. A general motion toward the west is expected to continue for another two or three days. On its anticipated track the center of Tropical Cyclone Gita could reach Tonga within 12 hours. Tropical Cyclone Gita will be capable of causing major wind damage when it reaches Tonga. Gita will also drop heavy rain and flooding is possible. Winds blowing the wind toward the coast could also produce significant storm surges in some locations.

Tropical Cyclone Gita strengthened on Saturday as it passed just to the east of Niue. Outer rainbands on the western side of Gita were bringing gusty winds and heavy rain to Niue. At 4:00 p.m. EST on Saturday the center of Tropical Cyclone Gita was located at latitude 19.2°S and longitude 168.8°W which put it about 85 miles (135 km) east-southeast of Niue. Gita was moving toward the south at 8 m.p.h. (13 km/h). The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 105 m.p.h. (165 km/h). The minimum surface pressure was 969 mb. Tropical Cyclone Gita was the equivalent of a hurricane/typhoon.

The circulation of Tropical Cyclone Gita became more symmetrical on Saturday. Several rainbands wrapped completely around the center of circulation. A clear area appeared at the center of circulation on visible satellite images, which indicated that an eye was forming. A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in the ring. Storms in the core of the circulation were generating upper level divergence which was pumping mass away from the tropical cyclone. Other rainbands were revolving around the core of Tropical Cyclone Gita.

Tropical Cyclone Gita will move through an area favorable for intensification during the next 24 to 48 hours. Gita will move over water where the Sea Surface Temperature is near 30°C. Tropical Cyclone Gita is moving around the eastern end of an upper level low, but the upper level winds are weak and there is not much vertical wind shear. There is drier air to the southwest of Gita, but it does not seem to be entering the circulation of the tropical cyclone. Tropical Cyclone Gita will continue to intensify and it could strengthen rapidly. Gita could strengthen into the equivalent of a major hurricane.

The upper level low is steering Tropical Cyclone Gita toward the south. Gita will turn toward the southeast in about 12 to 24 hours. When Gita reaches the southern side of the upper low, it will move toward the west. On its anticipated track Tropical Cyclone Gita will pass just to the southeast of Niue. Gita could approach Tonga in about 36 hours and it could the equivalent of a major hurricane at that time.

Tropical Cyclone Gita formed near Samoa on Friday. At 10:00 a.m. EST on Friday the center of Tropical Cyclone Gita was located at latitude 14.8°N and longitude 172.3°E which put it about 155 miles (250 km) west of Pago Pago, Samoa. Gita was moving toward the east at 18 m.p.h. (29 km/h). The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 989 mb.

Tropical Cyclone Gita was bringing gusty winds and heavy rain to Samoa. The strongest rainbands were north and east of the center of circulation. The bands south of the center consisted primarily of showers and low clouds. There appeared to be drier air in the southern half of the circulation which was inhibiting the development of taller clouds and stronger storms in that part of Gita. Thunderstorms in the rainbands north of the center of circulation were generating upper level divergence which was pumping mass away to the east of the tropical cyclone.

Tropical Cyclone Gita will be moving through an environment favorable for intensification. Gita will move over water where the Sea Surface Temperature is near 30°C. An upper level low south of Gita is producing easterly winds which are blowing toward the top of the circulation. Those winds are causing some vertical wind shear, but the shear does not appear to be strong enough to prevent intensification. The drier air in southern half of the circulation will inhibit intensification. However, if some of the rainbands north of the center wrap around the southern side of the center, then they could reduce the effects of the drier air. Tropical Cyclone Gita is likely to intensify into the equivalent of a hurricane/typhoon during the weekend.

The upper low south of Gita is currently steering the tropical cyclone toward the east. Gita will approach the eastern end of the upper low during the next 24 hours and it will move more toward the south. Tropical cyclone Gita will turn back toward the west when it moves south of the upper low. On its anticipated track Tropical Cyclone Gita will continue to bring gusty winds and heavy rain to Samoa for another 12 to 24 hours. Gita could pass near Niue in 24 to 48 hours and it could move near Tonga in about three days.

Tropical Cyclone Ella strengthened into the equivalent of a hurricane/typhoon as it moved near Wallis and Futuna on Thursday. Ella brought gusty winds and locally heavy rain to those islands. At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Ella was located at latitude 14.0°S and longitude 178.2°W which put it about 20 miles (30 km) north of Wallis and Futuna. Ella was moving toward the northwest at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 105 m.p.h. (170 km/h). The minimum surface pressure was 979 mb.

Tropical Cyclone Ella has a very small circulation, but that circulation is well organized. There is a very tight inner core. A ring of strong thunderstorms surrounds a tiny pinhole eye. The strongest winds are occurring in the tight eyewall. Additional bands of thunderstorms are forming in the eastern half of the circulation. There are bands of showers in the western half of the circulation. Winds to hurricane/typhoon force extend out only about 10 miles (15 km) from the center of circulation. Winds to tropical storm force extend out about 80 miles (130 km) from the center.

Tropical Cyclone Ella is moving through an environment favorable for intensification. Ella is moving over water where the Sea Surface Temperature is near 30°C. It is in an area where the upper level winds are weak and there is little vertical wind shear. Tropical Cyclone Ella could continue to intensify as long as it is in an area where the upper level winds are weak. However, there are much strong upper level westerly winds flowing just to the south of the tropical cyclone. If Tropical Cyclone Ella moves into an area where the upper level winds are strong, vertical wind shear could weaken it very quickly because of Ella’s small size.

A subtropical ridge south of Ella is steering the tropical cyclone toward the west and a general westerly motion is expected to continue for several more days. On its anticipated path Tropical Cyclone Ella will move away from Wallis and Futuna. Ella could move near the northeastern portion of Fiji in 24 to 36 hours.

Tropical Cyclone Ella strengthened on Wednesday as it moved closer to Wallis and Futuna. At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone Ella was located at latitude 14.4°S and longitude 177.0°W which put it about 75 miles (120 km) east of Wallis and Futuna. Ella was moving toward the west at 3 m.p.h. (5 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 989 mb.

The circulation of Tropical Cyclone Ella exhibited better organization on Wednesday. A circular eye with a diameter of 25 miles (40 km) was evident on some microwave satellite images. A ring of thunderstorms surrounded the eye. Additional bands of showers and thunderstorms developed in the eastern half of the circulation. Storms in the core of the circulation generated upper level divergence which pumped out mass and allowed the surface pressure to decrease. The size of the circulation of Tropical Cyclone Ella is small. Winds to tropical storm force only extend out about 100 miles (160 km) fro the center of circulation.

Tropical Cyclone Ella will move through an area that will be favorable for intensification. Ella will move over water where the Sea Surface Temperature is near 30°C. The upper level winds are weak and there is little vertical wind shear. Tropical Cyclone Ella could intensify into the equivalent of a hurricane/typhoon on Thursday. However, because the size of the circulation is small, any future increase in the vertical wind shear could quickly weaken Tropical Cyclone Ella.

Ella is moving around the northern side of a subtropical ridge, which is steering the tropical cyclone toward the west. Ella is currently moving north of a weaker section of the ridge and the steering winds are weaker. So, Ella is moving more slowly. The ridge is expected to steer Tropical Cyclone Ella in a general westerly direction during the next several days. On its anticipated track Tropical Cyclone Ella could pass near Wallis and Futuna in 12 to 18 hours. It could be near hurricane/typhoon strength at that time. Ella could approach the northeastern part of Fiji in two or three days.

Tropical Cyclone 19P formed southwest of Samoa on Monday. At 11:00 p.m. EDT on Monday the center of Tropical Cyclone 19P was located at latitude 15.2°S and longitude 173.3°W which put it about 100 miles (160 km) southwest of Apia, Samoa. It was moving toward the west-northwest at 6 m.p.h. (10 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1000 mb.

A small tight center of circulation formed within an area of thunderstorms south of Samoa on Monday. A thin primary rainband wrapped tightly around the center of circulation. Additional bands of showers and thunderstorms developed in the east half of the circulation. The bands of showers in the western part of the tropical cyclone were much weaker. Thunderstorms in the core of the circulation generated upper level divergence which pumped out mass. The circulation of Tropical Cyclone 19P is small. Winds to tropical storm force only extend out about 40 miles (65 km) from the center of circulation.

Tropical Cyclone 19P will be moving through an environment that will be marginally favorable for intensification. It will move over water where the Sea Surface Temperature is near 30°C. Tropical Cyclone 19P is under the eastern end of an upper level ridge which is producing southerly winds that are blowing toward toward the top of the circulation. The upper level winds are generating moderate vertical wind shear which is inhibiting upper level divergence to the south of the tropical cyclone. Given the marginal conditions Tropical Cyclone 19P could maintain its intensity or slowly strengthen. However, since the circulation is so small, a significant increase in vertical wind shear could also quickly weaken the tropical cyclone.

The same subtropical ridge that steered Tropical Cyclone Donna is also steering Tropical Cyclone 19P toward the west-northwest. A general westerly motion is expected for the next two or three days. On its anticipated track Tropical Cyclone 19P could approach Fiji in about 48 hours.

Tropical Cyclone Amos weakened as it sped past Samoa on Saturday. At 11:00 p.m. EDT on Saturday the center of Tropical Cyclone Amos was located at latitude 14.0°S and longitude 169.1°W which put it about 15 miles (25 km) north of Luma, Samoa. Amos was moving toward the southeast at 19 m.p.h. (31 km/h). The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h). The minimum surface pressure was 970 mb.

A ridge of high pressure east of Amos produced strong northwesterly winds which steered the tropical cyclone rapidly to the east-southeast on Saturday. Those steering winds carried the core of Amos just north of the larger islands of Samoa. Since hurricane force winds only extended out about 20 miles (30 km) from the center of circulation, the stronger winds stayed mostly over the open water. A weather station in Pago Pago, Samoa reported a wind gust of 54 m.p.h. (87 km/h).

Tropical Cyclone Amos is currently bringing wind and rain to the Manua Islands of eastern Samoa which include Olosega, Ofu and Ta’u. The rapid forward motion of Amos means that conditions should improve within a few hours.

The strong northwesterly winds are causing significant vertical wind shear that is rapidly weakening Tropical Cyclone Amos. Amos is still moving over water where the Sea Surface Temperature is near 30°C, but the vertical wind shear should continue to weaken the tropical cyclone as it moves farther east of Samoa.

Tropical Cyclone Amos strengthened as it passed over Iles Wallis and headed toward Samoa on Friday. At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Amos was located at latitude 12.5°S and longitude 175.4°E which put it about 70 miles (115 km) north-northeast of Iles Wallis and about 360 miles (580 km) west-northwest of Pago Pago, Samoa. Amos was moving toward the east at 11 m.p.h. (18 km/h). The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 125 m.p.h. (205 km/h). The minimum surface pressure was 956 mb.

The core of the circulation of Tropical Cyclone Amos is small but it is well organized. There is a ring of the thunderstorms around an eye, but clouds from the taller thunderstorms are obscuring the eye on conventional satellite imagery. Multiple bands of thunderstorms are rotating around the core of the circulation. The thunderstorms are generating well developed upper level divergence which is pumping out mass in all directions.

Tropical Cyclone Amos is an environment favorable for further intensification. It is moving over water where the Sea Surface Temperature is near 30°C. The winds in the upper levels are weak and there is not much vertical wind shear. Amos is likely to intensify during the next 24 hours and it could be the equivalent of a major hurricane when it reaches the western part of Samoa.

A ridge of high pressure is expected to steer Tropical Cyclone Amos toward the east-southeast during the nest several days. On its anticipated track Amos could be approaching the western islands of Samoa in a little over 24 hours. It could be the equivalent of a major hurricane at that time.

The Hurricane Intensity Index (HII) for Amos is currently 17.8. The Hurricane Size Index (HSI) is 9.0 and the Hurricane Wind Intensity Size Index (HWISI) is 26.8. Those indices suggest that the core of Tropical Cyclone Amos will be capable of causing major damage if it moves directly over any of the islands of Samoa. In addition, Amos will produce locally heavy rain capable of causing flash floods. It could also generate high waves and surges along the coasts of some of the islands.

Tropical Cyclone Amos intensified to the equivalent of a hurricane/typhoon on Thursday as it moved eastward across the South Pacific. At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Amos was located at latitude 12.4°S and longitude 177.1°W which put it about 80 miles (130 km) northwest of Iles Wallis. Amos was moving toward the east-northeast at 11 m.p.h. (18 km/h). The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h). The minimum surface pressure 974 mb.

Tropical Cyclone Amos is a small, tightly organized storm. A primary band of thunderstorms wraps almost entirely around the center of circulation and an eyelike feature is visible intermittently on satellite imagery. Additional bands of showers and thunderstorms are spiraling around the core of the circulation. The thunderstorms are generating upper level divergence which is pumping out mass in all directions and causing the surface pressure to decrease.

The environment around Tropical Cyclone Amos is very favorable for further intensification. It is moving over water where the Sea Surface Temperature is near 30°C. The upper level winds are very weak and there is little vertical wind shear. Amos will continue to intensify on Friday and it could intensify rapidly.

A subtropical ridge north of Amos is steering the tropical cyclone toward the east and that general motion is expected to continue for several more days. On its anticipated track Amos will pass near Iles Wallis on Friday. Although the core of strongest winds will pass north of Iles Wallis, It could still bring strong winds, heavy rain and large waves to those islands. On its anticipated track Amos could be approaching western Samoa within 36 hours. It could be a very strong tropical cyclone at that time.

A center of circulation developed within a large area of thunderstorms north of Fiji on Wednesday and the system was designated as Tropical Cyclone Amos. At 5:00 p.m. EDT on Wednesday the center of Tropical Cyclone Amos was located at latitude 12.5°S and longitude 179.4°W which put it about 145 miles (235 km) northwest of Ile Futuna. Amos was stationary. The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 989 mb.

The circulation near the core of Tropical Cyclone Amos is still organizing. A narrow primary band of thunderstorms is wrapping tightly around the core and an eye may be forming at the center of circulation. Several other thin bands of showers and thunderstorms are rotating around the outer portions of the circulation. The thunderstorms are generating some upper level divergence, but it is not well developed yet.

The environment is favorable for continued intensification. Amos is moving over water where the Sea Surface Temperature is near 30°C. The upper level winds are not very strong and there is little vertical wind shear. As the core of the circulation becomes more well organized, it will convert energy from the ocean more efficiently and the wind speeds will increase. Tropical Cyclone Amos could intensify into the equivalent of a hurricane/typhoon within 24 to 36 hours.

Tropical Cyclone Amos is currently in an area where the steering currents are weak. An upper level ridge is forecast to develop north of Amos and begin to steer the tropical cyclone toward the east. On its anticipated track Amos could pass near Iles Wallis in 24 to 36 hours. It could be approaching Samoa in two or three days.